1. Field of the Invention
The present invention relates to resin multilayer substrates and methods of manufacturing the same.
2. Description of the Related Art
An exemplary wiring board with a built-in semiconductor element is disclosed in WO 2011/108308. A wiring structure layer is formed in an upper portion of this wiring board. In this wiring structure layer, wiring lines are disposed on the upper surface of an insulating layer, with a protective insulating layer being disposed so as to cover the upper side of this insulating layer. It should be noted that the protective insulating layer has openings, through which the wiring lines are partially exposed.
A component is sometimes mounted on the surface of a resin multilayer substrate. In recent years, it has been desired to reduce the terminal size of, and the gap between, mounted components. It is difficult to appropriately address these needs, however, in a structure on which a component is mounted with a conductor pattern, such as copper foil exposed at a component mounting surface, interposed therebetween, as has been conventionally employed. The same applies to the structure of the wiring board described in WO 2011/108308, for example, because when a component is to be mounted on the topmost surface, the component will be mounted with a conductor pattern, which serves as the wiring lines partially exposed at the topmost surface, interposed therebetween.